ABSTRACT
Nitrate in surface and underground water caused systematic risk to the ecological environment. The electrochemically reduction of nitrate into ammonia (NO3RR), offering a sustainable route for nitrate containing wastewater treatment and ammonia fertilizer conversion. Exploration of catalyst with improved catalytic activity with lower energy barriers is still challenging. Here, we report a copper nitride (Cu3N) catalyst with moderate *NOx and *H2O intermediates adsorptions showed enhanced NO3RR performance. Density functional theory calculations reveals that the unique electronic structure of Cu3N provides efficient active sites for NO3RR, thus enabled balanced adsorption of *NO3 and *H2O (ΔE descriptor), sufficient active hydrogen, and moderate intermediate (*NO3 â HNO3, *NH2â*NH3) adsorption energy. Notably, the in-situ analysis technology revealed potential-driven reconstruction and rehabilitation of Cu3N, forming possible nitrogen vacancy, thus implied for better mechanism understanding. The NO3RR activity of Cu3N surpasses that of most recent catalysts and demonstrates superior stability and implies the application for NH4+ fertilizer recovery, which maintaining an NH3 Faradaic efficiency of 93.1 % and high yield rate of 2.9 mg cm2h-1 at -0.6 V versus RHE. These findings broaden the application scenarios of Cu3N catalyst for ammonia synthesis and provide strategy on improving NO3RR performance.
ABSTRACT
Global water bodies are increasingly imperiled by nitrate pollution, primarily originating from industrial waste, agricultural runoffs, and urban sewage. This escalating environmental crisis challenges traditional water treatment paradigms and necessitates innovative solutions. Electro-catalysis, especially utilizing copper-based catalysts, known for their efficiency, cost-effectiveness, and eco-friendliness, offer a promising avenue for the electro-catalytic reduction of nitrate to ammonia. In this review, we systematically consolidate current research on diverse copper-based catalysts, including pure Cu, Cu alloys, oxides, single-atom entities, and composites. Furthermore, we assess their catalytic performance, operational mechanisms, and future research directions to find effective, long-term solutions to water purification and ammonia synthesis. Electro-catalysis technology shows the potential in mitigating nitrate pollution and has strategic importance in sustainable environmental management. As to the application, challenges regarding complexity of the real water, the scale-up of the commerical catalysts, and the efficient collection of produced NH3 are still exist. Following reseraches of catalyst specially on long term stability and in situ mechanisms are proposed.
ABSTRACT
Gastrointestinal (GI) cancers, including colorectal cancer, pancreatic cancer, liver cancer and gastric cancer, are severe social burdens due to high incidence and mortality rates. Bromodomain and extra-terminal (BET) proteins are epigenetic readers consisting of four conserved members (BRD2, BRD3, BRD4 and BRDT). BET family perform pivotal roles in tumorigenesis through transcriptional regulation, thereby emerging as potential therapeutic targets. BET inhibitors, disrupting the interaction between BET proteins and acetylated lysines, have been reported to suppress tumor initiation and progression in most of GI cancers. In this review, we will demonstrate how BET proteins participate in the GI cancers progression and highlight the therapeutic potential of targeting BET proteins for GI cancers treatment.
ABSTRACT
Although lithium-sulfur (Li-S) batteries have long been touted as next-generation energy storage devices, the rampant dendrite growth at the anode side and sluggish redox kinetics at the cathode side drastically impede their practical application. Herein, a dual-functional fibrous skeleton implanted with single-atom Co-Nx dispersion is devised as an advanced modificator to realize concurrent regulation of both electrodes. The rational integration of single-atomic Co-Nx sites could convert the fibrous carbon skeleton from lithiophobic to lithiophilic, helping assuage the dendritic formation for the Li anode. Meanwhile, the favorable electrocatalytic activity from the Co-Nx species affording a lightweight feature effectively enables expedited bidirectional conversion kinetics of sulfur electrochemistry, thereby inhibiting the polysulfide shuttle. Moreover, the interconnected porous framework endows the entire skeleton with good mechanical robustness and fast electron/ion transportation. Benefiting from the synergistic effects between atomically dispersed Co-Nx sites and three-dimensional conductive networks, the integrated Li-S full batteries can achieve a reversible areal capacity (>7.0 mAh cm-2) at a sulfur loading of 6.9 mg cm-2. This work might be beneficial to the development of practically viable Li-S batteries harnessing single-atom mediators.
ABSTRACT
Inspired by natural photosynthesis, artificial heterojunction photocatalysts have been extensively studied. Herein, a novel ternary graphitic carbon nitride/platinum/bismuth vanadate (g-C3N4/Pt/BiVO4) photocatalytic system was successfully synthesized, where Pt/BiVO4 nanosheet is anchored on the surface of layered g-C3N4, as evidenced by structural observations. Ultraviolet photoelectron spectroscopy and ultraviolet-visible diffuse reflectance spectroscopy are carried out to identify the position of the conduction band and valence band. A Z-scheme is used to interpret the superior photocatalytic performance of g-C3N4/Pt/BiVO4 and further verified by the capture of free radicals and terephthalic acid photoluminescence experiments. Compared with the g-C3N4/BiVO4 binary system, the Z-scheme g-C3N4/Pt/BiVO4 photocatalyst not only possesses enhanced carrier separation efficiency but also maintains sufficient redox properties, thus inducing superior photocatalytic activity. More importantly, the novel Z-scheme photocatalyst exhibits excellent recycle stability, which could provide inspiration for the rational design of efficient and practical photocatalysts for environmental pollution treatment. The ternary photocatalyst also exhibits significantly enhanced visible-light photocatalytic hydrogen production performance.
ABSTRACT
Mass production of graphene powders affording high quality and environmental benignancy serves as a prerequisite for the practical usage of graphene in multiple energy storage applications. Herein, we exploit a salt-templated CVD approach to harness the direct synthesis of nitrogen-doped graphene (NG) nanosheets and related ink dispersions in a scalable, safe, efficient, and green fashion. Thus-fabricated NG accompanying large productivity, excellent electrical conductivity, and favorable solution processability possesses implications in printable energy storage devices. With the NG-based ink in hand, self-standing 3D architectures with programmable patterns can be directly printed over a myriad of substrates. Accordingly, both electrode preparation for flexible supercapacitors and separator modification in Li-S batteries can be enabled via printing by employing our NG-based composite inks. This work thus represents a practical route for mass production of graphene inks with cost-effectiveness and eco-friendliness for emerging energy storage technology.
ABSTRACT
A series of novel Bi2MoO6/zeolitic imidazolate framework-8 (ZIF-8) photocatalysts have been successfully fabricated through a facile self-assembly process. X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectrophotometry, and X-ray photoelectron spectroscopy (XPS) characterized pure Bi2MoO6, pure ZIF-8, and a series of Bi2MoO6/ZIF-8 composites. The result indicated that, when compared with pure Bi2MoO6, the composite of Bi2MoO6/ZIF-8 exhibited excellent photocatalytic performance for the degradation of methylene blue (MB) under visible light. Moreover, the Bi2MoO6/ZIF-8-3 composite (the molar ratio of Bi2MoO6 to 2-MI is 3:3) has optimum photocatalytic performance because of the suitable amount of ZIF-8 decorated on the flower-like Bi2MoO6. The enhanced photocatalytic activity is probably due to the introduction of ZIF-8, which will promote the separation of electron-hole pair and the surface morphology. Benefitting from the diversity of the MOF species (ZIF-8 is one of them), this composing strategy of Bi2MoO6/MOF composite would provide new insight into the design of highly efficient visible light photocatalysts.
ABSTRACT
BiFeO3/Reduced Graphene Oxide (BFO/RGO) composites have been fabricated by a simple hydrothermal method. The X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman, and X-ray photoelectron spectroscopy (XPS) analysis reveal that graphene oxide was reduced in hydrothermal process and BFO/RGO composites were successfully synthesized. UV-visible absorption and photoluminescence properties show that the introduction of RGO can effectively reduce the recombination of photogenerated electron and hole pairs. Compared to the pristine BFO, the photocatalytic performance of BiFeO3 Graphene Oxide (BGO) composites is enhanced for the degradation of Methylene blue (MB) solution under visible light irradiation, and the result shows that the optimal amount of Graphene Oxide (GO) in the composites is 60 mg (BGO60). The excellent photocatalytic performance is mainly ascribed to improved light absorption, increased reactive sites, and the low recombination rate of electron-hole pairs. This work can provide more insights into designing advanced photocatalysts for wastewater treatment and environmental protection.
ABSTRACT
With the method of litter bags, the characteristics of soil enzyme activities, soil microbial diversity at later stage of decomposition, and the relationships between soil enzyme activity and initial soil property were investigated in the process of stem and leaf decomposition of three typical herbs, i.e., Stipa bungeana, Artemisia sacrorum and Thymus mongolicus in the south Ningxia loess hilly region, Northwest China. The results showed that soil enzyme activity increased under different treatments after 480 d during stem and leaf decomposition. Soil sucrose activity (32.40 mg·g-1·24 h-1) and alkaline phosphatase activity (1.99 mg·g-1·24 h-1) were the highest in S. bungeana treatment. Soil urease activity (2.66 mg·g-1·24 h-1) was the highest in T. mongolicus treatment, and soil cellulase activity (1.42 mg·g-1·72 h-1) was the highest in A. sacrorum treatment. Soil cellulose activity at later stage of decomposition had significant positive correlation with initial microbial biomass carbon of soil. Soil cellulose activity at later stage of decomposition had significant negative correlation with initial nitrate nitrogen content of soil. Ace index, Chao index and Shannon index of soil bacteria and fungi in plant tissue addition treatments were higher than in the control. However, Simpson index was opposed. The stem and leaf decomposition significantly promoted the abundance and diversity of soil bacteria and fungi, accelerated the decomposition rate of stems and leaves, and promoted the cycle and transformation of soil nutrients.
Subject(s)
Enzymes/analysis , Plant Leaves , Plant Stems , Soil Microbiology , Soil/chemistry , Artemisia , Bacteria , Biomass , Carbon/analysis , Cellulose/analysis , China , Ecosystem , Fungi , Nitrogen/analysis , Poaceae , Thymus PlantABSTRACT
In order to explore the distribution characteristics of organic carbon of different forms and the active enzymes in soil aggregates with different particle sizes, soil samples were chosen from forest zone, forest-grass zone and grass zone in the Yanhe watershed of Loess Plateau to study the content of organic carbon, easily oxidized carbon, and humus carbon, and the activities of cellulase, ß-D-glucosidase, sucrose, urease and peroxidase, as well as the relations between the soil aggregates carbon and its components with the active soil enzymes were also analyzed. It was showed that the content of organic carbon and its components were in order of forest zone > grass zone > forest-grass zone, and the contents of three forms of organic carbon were the highest in the diameter group of 0.25-2 mm. The content of organic carbon and its components, as well as the activities of soil enzymes were higher in the soil layer of 0-10 cm than those in the 10-20 cm soil layer of different vegetation zones. The activities of cellulase, ß-D-glucosidase, sucrose and urease were in order of forest zone > grass zone > forest-grass zone. The peroxidase activity was in order of forest zone > forest-grass zone > grass zone. The activities of various soil enzymes increased with the decreasing soil particle diameter in the three vegetation zones. The activities of cellulose, peroxidase, sucrose and urease had significant positive correlations with the contents of various forms of organic carbon in the soil aggregates.
Subject(s)
Carbon/chemistry , Enzymes/metabolism , Forests , Grassland , Soil/chemistry , Cellulase/metabolism , Particle Size , Peroxidases/metabolism , Urease/metabolism , beta-Glucosidase/metabolismABSTRACT
The purpose was to characterize the effects of vegetation types on plant leaf and litter carbon (C), nitrogen (N), phosphorus (P), potassium (K) and C: N: P: K ecological stoichiometric characteristics in seven dominant plant species, including Robinia pseudoacacia, Syringa, Sophora viciifolia, Hippophae rhamnoides, Rosa xanthina, Artemisia sacrorum, Artemisia giraldii, of Zhifanggou Watershed on the Loess Plateau, China. This paper indicated the differences between the contents of C, N, P and K and the characteristics of ecological stoichiometric in the different vegetation types, including forest type, shrub type and grass type. Concentrations of C, N, P and K were measured, and C: N: P: K was estimated for different vegetation types. There were no significant differences in leaf C, N and P concentrations among the three vegetation types. But significant differences in leaf K concentration existed, and the K concentration in leaf was the highest in grass type, and the lowest in shrub type. The contents of C, N, P and K in leaf were much higher than those in litter, especially in shrub and grass types. The resorption efficiencies of C, N, P and K were different, and their ranges varied 6.16%-22.84%, 24.38%-65.18%, 22.38%-77.16% and 60.99%- 89.35%, respectively. Grass type had the highest C, P and K resorption efficiencies, and the lowest N resorption efficiency. Values of the N: P ratio in leaf varied in the range of 12.14-19.17, and varied in the range of 12.84-30.67 in litter. Values of the N: P ratio in leaf were the highest in shrub type (19. 17), and the lowest in grass (12. 14), indicating that the growth of shrub plants was limited by P, while the growth of grass plants was limited by N. The K concentration in leaf was significantly negatively correlated with values of the N: P ratio in leaf, and the K concentration in litter was significantly negatively correlated with values of the C: P ratio in leaf. Findings in this study highlighted the characteristics of accumulation and and return of leaf and litters nutrients during the different vegetation succession on the Loess Plateau.
